Microcellulose Production via High-Consistency Acid Hydrolysis
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Solution Overview
Problem
Existing methods for producing microcellulose are inefficient and costly, requiring mechanical disintegration and high-energy input, such as expensive extruders, which complicate the production process and increase energy consumption.
Innovation Solution
A process involving mild acid hydrolysis of fibrous cellulosic material at high consistency and temperature, with controlled acid concentration, in a reactor without essential compression, allowing for the production of high-quality microcellulose with a narrow particle size distribution without the need for mechanical disintegration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If mechanical disintegration is used after acid hydrolysis to produce microcellulose, then particle size can be reduced to micron range, but production process becomes complicated and energy consumption increases significantly (5-100 kWh/ton)
Solution Approach 1:
The patent replaces the mechanical disintegration system (refiner units with compression ratios of 3:1 to 10:1) with a chemical hydrolysis system using sulfuric acid at controlled temperatures (100-160°C) and pressures. The acid hydrolysis directly reduces cellulose fiber dimensions to micro-scale particles without requiring subsequent mechanical refinement, thereby eliminating complex mechanical disintegration equipment while achieving the desired particle size reduction.
Solution Approach 2:
The patent changes the operational parameters by conducting hydrolysis at elevated temperatures (100-160°C) and pressures, and by controlling acid concentration (1-5% sulfuric acid). These parameter changes enable direct production of microcellulose with 1-10 micron particle size, replacing the need for mechanical size reduction while maintaining process efficiency and reducing energy consumption.
2Productivity
If extruders are used for acid hydrolysis and mechanical disintegration, then microcellulose can be produced, but equipment cost and maintenance cost increase significantly
Solution Approach 1:
The patent employs a simpler, more economical reactor system instead of expensive extruder equipment. The process uses conventional acid hydrolysis reactors that can be easily manufactured and maintained, replacing costly extruders with high compression ratios. This substitution significantly reduces both initial equipment investment and ongoing maintenance expenses while maintaining productive microcellulose output.
Solution Approach 2:
The patent substitutes the mechanical extrusion system with a chemical hydrolysis system using sulfuric acid in a reactor. This replacement eliminates the need for expensive extruder machinery while achieving the same microcellulose production objective, thereby reducing equipment costs and maintenance requirements.
3Manufacturing precision
If high compression ratio extrusion is used for intimate contact between cellulose and acid, then hydrolysis efficiency improves, but mechanical energy input increases to at least 100-150 kWh per dry ton
Solution Approach 1:
The patent replaces mechanical compression with chemical action by using sulfuric acid at elevated temperatures (100-160°C) and pressures. The thermal energy and chemical reactivity of the acid system provide sufficient contact and reaction efficiency without requiring high mechanical energy input, thereby achieving effective hydrolysis with minimal mechanical energy consumption.
Solution Approach 2:
The patent changes the energy input method from mechanical compression (100-150 kWh/ton) to thermal energy input at controlled temperatures (100-160°C) and pressure. This parameter change maintains hydrolysis efficiency through chemical reaction conditions while dramatically reducing mechanical energy requirements.
4Quantity of substance
If dilute sulfuric acid at low consistency is used for hydrolysis, then hydrolysis can proceed, but amount of acid based on dry weight of cellulose is high
Solution Approach 1:
The patent optimizes the consistency parameter to 3-50% (significantly higher than conventional low consistency methods) and adjusts acid concentration to 1-5% sulfuric acid. This parameter combination increases the effective concentration of acid relative to cellulose, reducing the total amount of acid required per unit of dry cellulose while maintaining effective hydrolysis reaction rates.
Solution Approach 2:
The patent changes the consistency dimension from low (conventional) to high (3-50%), which fundamentally alters the mass balance and acid consumption. By operating at high consistency, the process reduces the volume and mass of acid solution needed, thereby reducing acid consumption and associated costs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process efficiently produces microcellulose with a narrow particle size distribution and high purity, reducing energy input and production costs, while allowing for easy control of particle size through varying hydrolysis conditions.
Implementation Method 1
subjecting fibrous cellulosic material to acid hydrolysis at a temperature of at least 140°C and at a consistency from 15 to 50% on dry weight of the cellulose, wherein the amount of added acid is from 0.2 to 2% on dry weight of the cellulose
Data Source
Figure 1~3
Figure 4~5
AI summary
The present invention relates to a process for producing microcellulose comprising subjecting fibrous cellulosic material to acid hydrolysis at a temperature of at least 40°C and at a consistency of at least 8% on dry weight of the cellulose, wherein the amount of added acid is from 0.2 to 2%, preferably from 0.5 to 1.5% on dry weight of the cellulose.